A CDE Definition

A high-level language for describing the layout of a page to be displayed or printed. The two major languages are Adobe's PostScript and HP's PCL, which are device independent and built into most printers. Adobe's PDF format is also widely used for printing as well as publishing on the Web (see PostScript, PCL and PDF). The standard for page-oriented XML documents is XSL-FO (see XSL).

It's Done in the Printer
With regard to PostScript and PCL, much of the character and graphics shaping is done within the printer rather than in the user's computer. Instead of downloading an entire font (containing the design of each and every character) from the computer to the printer, a command to build a particular font is typically sent, and the printer creates the characters from font outlines.

Likewise, in a similar way, a command to draw a circle is sent to the printer rather than sending the actual bits of the circle image. However, bitmaps can also be used when necessary.